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===DFL===
===DFL===
In 1981 a variant of the DFV was produced specifically for use in the new [[Group C]] (and later C2) [[sports car racing]] categories. The engine was modified to a larger capacity (3955 cc for Group C, 3298 cc for C2) with both wider bore and longer stroke dimensions than the standard DFV, and was tuned for reliable power during endurance events. Named the DFL (for ''long-distance'') the engine found many uses during the mid-1980s, and was particularly successful in the C2 category, powering many cars, including prolific [[Spice Engineering|Spice]] and [[Tiga Race Cars|Tiga]] vehicles, to class victories around the world. The full Group C version never achieved the same sucess as its smaller sibling, but was used to power the famous [[Ford Supervan]] and [[Ford Supervan 2|Supervan 2]] promotional projects.
In 1981 a variant of the DFV was produced specifically for use in the new [[Group C]] (and later C2) [[sports car racing]] categories. The engine was modified to a larger capacity (3955 cc for Group C, 3298 cc for C2) with both wider bore and longer stroke dimensions than the standard DFV, and was tuned for reliable power during endurance events. Named the DFL (for ''long-distance'') the engine found many uses during the mid-1980s, and was particularly successful in the C2 category, powering many cars, including prolific [[Spice Engineering|Spice]] and [[Tiga Race Cars|Tiga]] vehicles, to class victories around the world. The full Group C version never achieved the same success as its smaller sibling, but was used to power the famous [[Ford Supervan]] and [[Ford Supervan 2|Supervan 2]] promotional projects.


== Major successes ==
== Major successes ==

Revision as of 20:41, 21 August 2007

A Ford Cosworth DFV on a Ligier JS11

The DFV (Double Four-Valve) engine was a Formula 1 engine produced by Cosworth. Its development in 1967 for Colin Chapman's Team Lotus was sponsored by Ford. The engine was a 90 degree 3 litre V8, and produced over 400 bhp from the start, reaching over 500 bhp by the end of its remarkable Formula 1 career. For many years it was the dominant engine in Formula One, and it was also used in other categories, including CART, Formula 3000 and Sportscar racing.

History

Formula One

Following the change to a 3-litre formula at the start of 1966, Colin Chapman approached the Ford Motor Company with the idea for the engine, which had to be specially made so that it could take the stresses it would face through being a structural part of the car. Ford then approached Keith Duckworth, previously a gearbox engineer at Lotus but now running his Cosworth company with Mike Costin, and paid him to design and build the engine for them.

The engine was not ready until the third race of the 1967 season at Zandvoort, but its debut proved electric. Graham Hill put his DFV-powered Lotus 49 on pole position by half a second, and Jim Clark stormed home to win. However, this dominant performance belied a serious fault in the timing gear.[1] Clark took three more wins that season, but reliability problems left him 3rd in the drivers' championship, 10 points behind Denny Hulme. The progress of the engine was documented in a film produced by the Ford Motor Company's film section, entitled "Nine Days in Summer".

The engine was so competitive that at the end of 1967 Ford had to gently explain to Colin Chapman that he would no longer have a monopoly on it in 1968, but the Lotus boss took it with good grace. What followed was a golden age, where teams big or small could buy an engine which was competitive, light, compact, and relatively cheap (£7,500 at 1967 prices[2] or about £90,000 in 2005 money[3]). The DFV effectively replaced the Coventry Climax as the standard F1 powerplant.

The classic DFV engine - Hewland gearbox combination, mounted in the rear of a 1978 Tyrrell 008.

Lotus, McLaren, Matra, Brabham, March, Surtees, Tyrrell, Hesketh, Lola, Williams, Penske, Wolf and Ligier are just some of the teams to use the DFV, and in 1969 and 1973 every World Championship race was won by DFV-powered cars, with the engine taking a total of 155 wins from 262 races between 1967 and 1985. The advent of ground effect aerodynamics on the F1 scene in 1977 provided a new lease of life for the now decade-old engine. The principle relied on Venturi tunnels on the underside of the car to create low pressure regions and thus additional downforce. Previously, teams running flat-12 engine configurations (most notably Ferrari) had enjoyed a handling advantage because of the low centre of gravity in such a configuration. However for ground effect, the wide-angle engine was completely the opposite of what was required: the cylinder heads protruded into the area where the Venturi tunnels should have been. In contrast, the V-configuration of the Cosworth engine angled the cylinders upwards and left ample space under the car for the necessary under-body profile.[4] Whilst BRM and Matra V12s were also available on similar customer terms to the DFV, and would also have been suited to ground effect aerodynamics, as Tyrrell's designer Derek Gardner explained, "...no-one wanted [the Matra engine] because all the horsepower went down the exhaust pipes, and no-one wanted a BRM engine for much the same reasons!"[5]

The onset of the turbo era in the early 1980s put an end to the DFV's F1 activities, as even with modifications the 15-year-old engine could not hope to compete with the vast power being put out by the new 1.5 litre turbocharged engines. For a few years, between 1977 when Renault debuted the powerful but unreliable turbo engine, and 1982 when the DFV-powered teams began to negotiate deals for turbo engines of their own, a competitive equilibrium was established.[6] Michele Alboreto took the DFV's last F1 win in a Tyrrell at Detroit in 1983, and Martin Brundle was the last person to race in F1 with a DFV, also in a Tyrrell at the Austrian Grand Prix in 1985.

Other formulae

The DFV's success was by no means limited to Formula 1, with the engine being used in sportscar racing with some modest success. The design of the crankshaft caused vibrations that caused reliability problems in endurance racing. The first such vehicle to use the DFV was Ford's own P68, built as early as 1968. However, this car, and its derived sister the P69, failed to finish a single race. Seven years after it was introduced, the engine won the Le Mans 24 Hours twice, first in the Gulf-sponsored Mirage driven by Jacky Ickx and Derek Bell in 1975, then with the surprise winners Rondeau in 1980, driven by Jean Rondeau and Jean-Pierre Jaussaud.

The DFV was also the engine for which the Formula 3000 series was created in 1985, and thus it won every race that year. The DFV and its variants continued racing in F3000 for a decade, Pedro Lamy taking the last win for a DFV in top-class motorsport, at Pau in 1993, its 65th F3000 win in 123 races.

Variants

DFW

The first variant produced from the DFV was a reduced-capacity unit for the Australia and New Zealand-based Tasman Series races of 1968-69. The changes between the DFV and DFW specification were limited to a reduced stroke, taking capacity to 2491cc and reducing power output to ~360 bhp.[7] This was the smallest capacity variant of the DFV that was officially produced by Cosworth. The engine was a direct replacement for its DFV parent in Lotus's 49s. The small engine proved just as competitive as the larger version; and Jim Clark took four victories in 1968, followed by one win for Piers Courage and brace of victories for Jochen Rindt in 1969. After the demise of the 2.5L Tasman formula following the 1969 season, the four DFW engines were converted to DFV specification.

Formula one

The DFV had three major upgrades over its life in the top formula, with the development of first the DFY and then the DFZ, followed by a major redesign to produce the final DFR type.

DFY

With the introduction of turbocharged engines towards the end of the 1970s, Cosworth's naturally-aspirated DFV began to lose its predominance. In an attempt to recover some of the performance deficit Cosworth designer Mario Illien reconfigured the cylinder aspect ratio to allow the engine to rev more freely, and combined this with a narrow-angle valve set-up. The changes upped power output to ~520 bhp,[7] but this was not sufficient to keep pace with the turbo cars at most tracks, and it was only through a modicum of luck that Michele Alboreto was able to take what would prove to be the DFV-family's final F1 victory, at the 1983 Detroit Grand Prix. The DFY lived on with back-marker teams until the end of the 1985 season, when Cosworth switched their efforts to supporting the new turbocharged Ford GBA V6.

DFZ

The announcement at end of the 1986 season that turbocharged cars would be banned from 1988, and the introduction of the Jim Clark Cup and Colin Chapman Trophy championships for naturally-aspirated cars for 1987, prompted Cosworth to revive their elderly engine design. This resulted in the DFZ, essentially an updated version of the final DFY design. However, the capacity increase for the new 3.5L naturally-aspirated formula running alongside the 1.5L turbos in 1987 allowed Cosworth to increase the power output of the unit to ~560 bhp.[7] The engine was intended as a temporary measure to tide smaller teams over into the new, non-turbo era from 1988 onwards. Tyrrell, AGS, March, Lola and Coloni chassis were all powered by Cosworth in 1987. Jonathan Palmer of Tyrrell eventually won the drivers' Jim Clark Cup, and his team took the constructors' laurels in the Colin Chapman Trophy. The engine remained in service with minor teams until the end of the 1988 season, when general release of the DFR engine made it obsolete.

DFR

From 1987 Benetton had been operating as the works Ford team. With the abandonment of turbocharging it was clear that the venerable DFV/Y/Z design was nowhere near being competitive with far newer offerings from Renault and Honda. To counter this, drastic changes were made for the DFR of 1988. Although superficially a DFV-design, almost the only feature carried over from previous versions into the DFR was the basic 90° V8 engine architecture. The DFR became available to all customers in 1989, with the Benetton team also using this engine until the 1989 French Grand Prix. The DFR struggled on until the 1991 season finally being eclipsed by the higher revving abilities of new pneumatic valve gear engines such as the HB, and was last used in that year's Australian Grand Prix by the Footwork, Fondmetal, Larrousse and Coloni teams, nearly a quarter of a century after the DFV's first race. By the time of its demise, continued improvement had pushed the DFR power output to nearly 630 bhp,[7] 60% higher than the original 1967 DFV.

North American series

DFX

A 2.65L turbocharged version of the DFV was developed privately by the Vels Parnelli Jones team for the 1976 USAC season. Cosworth became involved in the project soon after, and the engine was henceforth known as the DFX. It went on to dominate American Indycar racing in much the same way the DFV had dominated Formula 1, winning the Indy 500 10 years running from 1978 to 1987, and winning all USAC and CART championships between 1977 and 1987. By the time it was replaced the DFX was developing over 840 bhp.[7]

DFS

In 1988 GM financed the British Illmor firm to build a competitor to the DFX. The resulting motor owed not a little in its design to company founder Mario Illien's DFY design of five years previously. However, Ford responded by commissioning Cosworth to redesign the DFX to include a number of DFR improvements. The resulting DFS engine ran throughout 1988 and 1989, but proved to be nowhere near as successful as its forebear.

DFL

In 1981 a variant of the DFV was produced specifically for use in the new Group C (and later C2) sports car racing categories. The engine was modified to a larger capacity (3955 cc for Group C, 3298 cc for C2) with both wider bore and longer stroke dimensions than the standard DFV, and was tuned for reliable power during endurance events. Named the DFL (for long-distance) the engine found many uses during the mid-1980s, and was particularly successful in the C2 category, powering many cars, including prolific Spice and Tiga vehicles, to class victories around the world. The full Group C version never achieved the same success as its smaller sibling, but was used to power the famous Ford Supervan and Supervan 2 promotional projects.

Major successes

DFV normally-aspirated 3.0 litre 90 degree V8

F1 Drivers' Champions (12):

F1 Constructors' Champions (10):

  • 1968 Lotus,
  • 1969 Matra,
  • 1970 Lotus,
  • 1971 Tyrrell,
  • 1972 Lotus,
  • 1973 Lotus,
  • 1974 McLaren,
  • 1978 Lotus,
  • 1980 Williams,
  • 1981 Williams

Le Mans 24 Hours winners (2):

Formula 3000 Champions (6):

DFX turbocharged 2.65 litre 90 degree V8

Indy 500 winners (10):

USAC Champions (3):

CART Champions (9):

References

  1. ^ Howard, K. (2007) Relative values. Motor Sport, 83(7), 40-43.
  2. ^ Hilton, Christopher (2002) Ken Tyrrell - Portrait of a Motor Racing Giant p38 Haynes Publishing ISBN 1-85960-885-X
  3. ^ EH.net How much is that worth today? [1]
  4. ^ Hughes, Mark (2004) The Unofficial Complete Encyclopedia of Formula 1 p 55 Lorenz Books ISBN 0-7548-1509-9
  5. ^ Hilton, Christopher (2002) Ken Tyrrell - Portrait of a Motor Racing Giant pp68-69 Haynes Publishing ISBN 1-85960-885-X
  6. ^ Hughes, Mark (2004) The Unofficial Complete Encyclopedia of Formula 1 p 62 Lorenz Books ISBN 0-7548-1509-9
  7. ^ a b c d e Robson, G. (2007) Cosworth DFV: Horses for courses. Motor Sport, 83(7), 44-48.
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